A Douglas DC-10 under construction
There was a time when Douglas made more airliners than anybody else.
During the 1940s the Douglas DC-3 accounted for around ninety per cent of
all commercial airline travel, and well into the 1950s Douglas was the world leader. But the company was late to switch to
jets, after which it spent the rest of its life on the back foot. It briefly gained the initiative with the DC-9, but only briefly, and in 1967 it was forced to merge with
McDonnell. The rise of Airbus in the 1980s spelled doom for McDonnell-Douglas, and in 1997 the company was bought by Boeing, after which
it ceased to exist. There's some debate as to how much of Douglas survives
within Boeing, but at the very least the name is no longer used for
jetliners.
Douglas was founded in 1921 by Donald Douglas, who was born in 1892. He
was one of those old-school aviation pioneers who was born before heavier-than-air flight and lived long enough to see people walk on the
moon. He learned his trade working for Glenn-Martin during the
1910s, before deciding to go it alone in the 1920s. In 1924 a pair of converted Douglas DT torpedo bombers became the first aircraft to circumnavigate the Earth, taking fifteen days, with multiple stops along the way. The stunt established the company's reputation for robust construction,
after which Douglas concentrated on military contracts.
A DC-3
In 1932 Trans-World Airlines floated a request for a metal-skinned
airliner. Ironically, given the subsequent course of world events, Donald
Douglas was worried that Depression-era America was poised to cut defence spending, so he decided to submit a design. The DC-1, for Douglas Commercial 1, didn't quite meet TWA's requirements - it had two engines instead of three - but it won the competition. With its all-metal construction, low wing, and retractable undercarriage it was state-of-the-art. After further development
the DC-1 evolved into the stretched, re-engined DC-2 of 1934, followed by the
widened DC-3 of 1936.
The DC-3 went on to sell over 600 units, some of which are still flying
today. By itself that made the DC-3 the best-selling airliner of the 1940s, but it was comprehensively overshadowed by the C-47 Skytrain, a
militarised version of the DC-3 that made its first flight a few days
before the United States entered the Second World War. In the years that
followed Douglas built over 10,000 C-47s, many of which were converted after the war into airliners. Simultaneously the Soviet Union
constructed over 4,000 licence-built Lisunov Li-2s, which were based on
the DC-3 but had the cargo door arrangement of the C-47.
The airframe was so popular that it was even used by the Axis powers.
Japan made over 400 modified DC-3s, having purchased a licence a few years
before the war broke out. Lufthansa of Germany even operated a small fleet
of DC-3s requisitioned from KLM of the Netherlands. The DC-3 remained
popular in the post-war years and a handful of turboprop conversions are
still flying today. It's an iconic aircraft.
Douglas' first post-war airliner was the DC-6, a piston-engined design
that entered service in 1947. It was popular, but its success convinced
Douglas that there was no reason to switch to jets just yet. As mentioned elsewhere in this series of articles the post-war US aviation industry didn't feel the same existential
pressure to modernise as its European contemporaries, so for
a few years the US giants - Douglas, Lockheed, and Convair - continued to
sell piston airliners, while the likes of Vickers, de Havilland, and
Sud-Aviation switched to turboprops and turbojets instead.
Douglas followed the DC-6 with the larger, faster DC-7, which entered
service in 1953, at more or less exactly the same time as the jet-powered
de Havilland Comet and the turboprop Vickers Viscount. The Comet's success
was short-lived, but the Viscount was popular enough to sell to airlines
in the United States, which worried the US aviation industry. One company that wasn't worried, however, was Boeing.
Boeing's pre-war airliner designs had all been technically advanced, but not
especially popular, and during the war the company concentrated on multi-engined
bombers such as the B-17 and B-29. After the war Boeing found itself in
much the same position as post-war Europe. It needed to make a bold
gesture in order to remain relevant, so in 1950 the company announced a project to
design a new jetliner. Developing a jetliner was not cheap, but the success of the Comet and the Viscount convinced Boeing that it was on the right track.
A Douglas DC-7 fire-bomber
A Boeing B-47 bomber-bomber
Boeing had built up expertise in
building multi-engined, swept-wing aircraft with the B-47, which
entered service in 1951. By 1954 the company had a jetliner prototype, the
Dash-80. It had a low wing, an even number of engines mounted in pods beneath the wings, and a
low-mounted tailplane, essentially the same configuration as every modern
jetliner, not least because subsequent Boeing designs used the same basic
fuselage design.
Shortly after the Dash-80's first flight the US Air Force picked a
derivate of the aircraft as the basis of a new, jet-powered aerial
refuelling tanker. The tanker competition demonstrated how far the US
aviation industry had started to lag behind. Technically
Lockheed won the contract, but it didn't have a prototype. Its entry
was still just a design study, and in the end the company withdrew without ever building an aircraft. Douglas submitted a design of its own, but again
the aircraft only existed on paper. Only Boeing had an actual
physical product in the air.
To its credit Douglas managed to rapidly catch up. After two years of
design studies Douglas announced its own jetliner, the DC-8, in 1955.
The specification was very similar to the 707, with four engines in pods
under the wing, and sufficient range to cross the US non-stop and the
Atlantic with a stop for fuel. One thing the DC-8 had over Boeing's design was a fuselage wide enough
for six-abreast seating, with a passenger load of around 170 people. In
contrast the early Boeing 707 prototypes had a narrower fuselage that
could only seat around 120-140 passengers, and as a consequence the 707's
development was delayed so that Boeing could widen the aircraft to match
the DC-8.
Douglas hoped that US airlines would hold off on choosing a jetliner,
because the technology was still new and Douglas had a solid reputation, but the 707 was an immediate success, and ultimately the DC-8 never
managed to regain the ground Douglas had lost.
It's hard to write about the DC-8. Along with the 707 it was the prototype
of all modern airliners, but to modern eyes it doesn't look revolutionary.
Beyond its distinctive nose intakes - for cabin pressurisation and air
conditioning - it had the same configuration as any modern jetliner, with
engines in pods under the wing and a low-mounted tail. At the time
pod-mounted engines were unusual. The Comet and Avro Jetliner had engines
buried in the wings, while the Caravelle had rear-mounted engines. Pods interfered with airflow over the wing, but they had some
advantages, including easier access and lower cabin noise. There was also
no chance of turbulent air from the wings entering the engine intakes, and the
weight counteracted the natural tendency of the wing to bend upwards in
flight.
The original DC-8 was powered by turbojet engines of a type that was
shared with early models of the B-52 bomber. Whenever it took off it left
behind smoke trails of unburned fuel. The fine points of engine
design are outside the scope of this document but suffice it to say that turbojets produce all of their thrust by
venting expanded, superhot air from the back of the engine, which works
well at cruising speed but is very inefficient during take-off.
From the
early 1960s virtually all airline manufacturers switched to turbofan
engines, which use some of the exhaust gas to power a multi-bladed fan mounted in
front of the air intake. The fan generates thrust directly, very much like a turboprop, but because the fan blades are tightly encased
in a cowling the tips of the blades can approach the speed of
sound without generating the noisy sonic booms that limit the
top speed of propeller blades.
For many years NASA used a re-engined, turbofan-powered DC-8 as a flying
laboratory.
In the late 1950s Douglas upgraded the DC-8's engines with turbofans,
which gave the DC-8-50 - the most popular variant - true non-stop
transatlantic range. Sales still lagged behind the Boeing 707, but in the mid-1960s Douglas stretched the design into
the Super DC-8, which had a potential passenger capacity of around 250,
unusually large for the time.
This gave the DC-8 a second wind, and in
1969 and 1970 the DC-8 actually managed to outsell the 707, although the
introduction of the Boeing 747 quickly overshadowed it. Production ceased
in 1972, by which time Douglas had sold around 550 DC-8s, versus just over
a thousand Boeing 707s, a figure that included the shortened Boeing 720. The DC-8 was apparently very robust, and from 1979 onwards
several airlines opted to re-engine their DC-8s with modern CFM56
turbofans, the same engines that powered the contemporary Boeing 737 and
Airbus A320. Ultimately 110 DC-8s were converted to use the new, more
fuel-efficient engines, and several dozen of them remained in service as
cargo aircraft well into the twenty-first century.
As mentioned earlier it's hard to write about the DC-8. Its configuration
was unusual at the time but is now standard, albeit that it had two more
engines that most modern airliners. It was outsold by the Boeing 707, and
throughout its life it had a solid safety record. DC-8s were involved in
several fatal accidents, but the vast majority were the result of human
error or bad luck. On a personal level I have never flown in one, in fact the only British operators of the DC-8 were cargo airlines, and then only briefly in the late 1970s.
I wrote at the beginning of this document that Douglas only made three
airliners. Technically it only made two. The second was the DC-9, which
entered service in 1965. In 1967 Douglas merged with McDonnell to become
McDonnell-Douglas, and the final design, the DC-10, was a
McDonnell-Douglas aircraft, but I'm going to continue to use the Douglas
name because it's easier to type.
Let's talk about the DC-9. To paraphrase Jane Austen, "it is a truth
universally acknowledged that an aircraft manufacturer in possession of a
mid-sized airliner must be in want of a smaller, regional airliner to
flesh out its fleet and perhaps create vertical synergies", and so it was
with Douglas. Immediately after work began on the DC-8 Douglas realised
that it needed a range of different airliners if it was going to compete
with Boeing, so the company teamed up with Sud-Aviation to licence-build
Caravelles. In the end nothing came of this - the Caravelle was
surprisingly unpopular in the US - so Douglas designed its own short-range
airliner instead.
The resulting DC-9 had essentially the same specification as the
Caravelle, with twin engines mounted on either side of the rear fuselage
and a T-tail. It entered service in 1965, beating the Boeing 737 by almost
two years. In retrospect it was Douglas' high water mark, a genuinely
desirable product that came to market before the competition and outsold it. By the time the Boeing 737 entered service Douglas had stretched the
DC-9 into the DC-9-30, which carried more passengers than the original 737
over a similar distance, while burning less fuel. Boeing eventually caught
up with the stretched, re-engined 737-200, and gradually pulled ahead, but
ultimately sales figures were almost neck-and-neck, with 976 DC-9s vs
1,114 original 737s.
Unfortunately for Douglas the success of the DC-9 turned out to be a major
problem. Boeing managed to keep development costs of its jetliners down by
reusing elements of the original 707. The 727, 737, and 757 all had essentially the same fuselage, with the 707 and 727 also sharing
cockpits.
The DC-9 on the other hand was a completely fresh design. On the positive side the DC-9 exceeded Douglas'
sales targets even before it had been launched, but the company found
itself overwhelmed by the flood of orders. It was unable to build aircraft
fast enough to meet demand, which led to expensive litigation. To make
things worse the Vietnam War meant that Douglas' engine supplier, Pratt
and Whitney, was similarly overwhelmed by military demand for its engines.
As a result Douglas found itself stockpiling fuselages that had no
engines, and eventually in 1967 the company merged with McDonnell.
An MD-80
The DC-9 was replaced in the early 1980s by the McDonnell-Douglas MD-80,
which had more powerful engines and an enlarged wing. Passenger load went
up to around 150, with a range of around 2,500 miles, which made it a lot
more attractive to operators outside the US. Most of the DC-9's operators
had been in the United States, but the MD-80 sold extensively to operators
in Europe and the Far East.
The MD-80 turned out to be MDD's most popular jetliner, selling over a
thousand units. On paper this was great news, but the 1980s saw a huge
expansion of the aviation market. Global passenger flights almost doubled
over the decade, and so although the MD-80 was popular, the competition was more popular still. Boeing ended up selling almost twice as many 737 Classics in
this new, larger market, and there was another problem in the form of
Airbus.
The first Airbus, the A300, was a hard sell, but in the end
it caught on - tapping into a new market for long-range twin-jets - and
from that point onwards Douglas found itself squeezed between Boeing and
Airbus. Donald Douglas himself didn't live to see it, having passed away in 1981, which is perhaps for the best. In the mid-80s Airbus launched the A320, a short-to-mid-range jet
that ended up outselling even the Boeing 737. It was slightly larger and
longer-ranged than the 737, which in the mid-80s was getting long
in the tooth, and so operators who wanted to replace their 737s opted for
A320s instead. At the smaller end of the market McDonnell-Douglas' sales were nibbled away by a new wave of regional jets.
The MD-80 was too big to work as a regional jet, but not big enough to
compete with the new 737 or A320, so MDD decided to stretch it. The resulting
aircraft was launched in the early 1990s as the MD-90, essentially an
MD-80 with a slightly longer fuselage and more efficient engines. Compared
to the original DC-9 it was almost fifty feet longer. It had a distinctive
look, almost like a flying pencil. In terms of passenger load it was on a
par with the competition, but it lacked range, and in the end MDD only
sold 116 of them, while the contemporary Boeing 737 and Airbus A320 models
sold around 7-8000 units each.
In the early 1990s MDD announced the MD-95, which was an MD-90 shortened
to the length of the original DC-9, but with the improved wings and
engines of the later models. But MDD never had a chance to build it,
because in 1997 the company was bought by Boeing. At the time MDD still made a lot of
money from military contracts, and it was more a merger than a sale, but
that was essentially the end for MDD's civilian airliner programme.
A Boeing 717
The MD-95 production line had been set up, so Boeing decided to continue
selling the aircraft as the Boeing 717. It slotted nearly into Boeing's
range beneath the 737, which by the late 1990s had grown into what would,
by 1960s standards, have been a mid-sized mainstream airliner. After launch in 1999 the 717
turned out to be surprisingly popular, with sales of over 150 units, but it was struck by the general aviation downturn that followed 9/11, and production ceased in 2006. As of this writing around a hundred 717s remain in
service, none in Europe. A few DC-9s and MD-80s remain flying as cargo
or charter aircraft.
As with the DC-8 it's hard to write about the DC-9 and its heirs. It had no obvious
design flaws and wasn't involved in any major controversies. The fact of
it being a short-to-mid-range airliner meant that it had none of the
glamour of the transatlantic giants, although its look - a thin fuselage
with engines at the back - was attractive. In the UK they were a fairly common sight on account of the fact that Swissair and SAS both had large MD-80 fleets.
This leads us to the last Douglas airliner, the widebody DC-10. It was
designed in the mid-1960s, at a time when the passenger aviation market
was rapidly expanding. The industry anticipated a need for a large,
high-capacity jet with enough range to cross the Atlantic. A kind of
airbus, and surprisingly the term predated the airline company.
Boeing responded with the huge, four-engined 747. For a while the 747
seemed like an extravagance, so there was room for a slightly smaller
widebody jet. Despite the troubled development of the C-5 Galaxy, Lockheed
decided to re-enter the airline market. They came up with the three-engined L-1011 Tristar. Meanwhile
Douglas developed a three-engined airliner of their own, the DC-10. In
terms of specification the two aircraft were very similar, with passenger
loads of around 250-270-300 depending on seating classes, and range of
around 3,000-5,000 miles depending on variant.
The two aircraft were visually very similar as well. They both had three
engines, two in pods beneath the wing and one in the tail. The DC-10's
engine was hung behind the tail, with the intake pipe running in a
straight line, while the Tristar's third engine was mounted at the rear of
the fuselage, with an intake that curved down to meet it.
The Lockheed L-1011's third engine was mounted at the rear of the
fuselage (top) while the Douglas DC-10's third engine hung behind the
tail in a cleverly-designed cradle.
Why three engines? Trijets were fairly common in the 1960s and 1970s. The
first designs, such as the Hawker Trident and the Boeing 727, were
intended to fill the gap between small regional jets and the four-engined
transatlantic airliners of the day, with the third engine adding extra
oomph. Propeller-driven airliners often had a third
engine mounted in the nose, but that wasn't practical for a jetliner, so
the logical place to put the engine was the tail. The market for
small trijets survived into the 1970s - the Trident and 727 were
eventually joined by the Russian Tu-154 and Yak-42 - but by the 1980s a
new generation of high-bypass turbofans killed them all off. The extra
power of a third engine wasn't worth the complexity and expense.
There was another reason for three engines. ETOPS, which stands for "extended operations", or "extended-range twin-engined operation standards" depending on who you ask. In
the 1960s and 1970s aviation rules were such that twin-engined airliners
couldn't practically cross the Atlantic. They were forbidden from flying
more than sixty minutes away from a diversion field in case one of the
engines failed. But ETOPS didn't apply if an aircraft had more than two
engines, so the 1960s and 1970s saw the rise of the
transatlantic trijet. They remained in service until the 1990s, at which
point further revisions to ETOPS rules meant that a new generation of
large, twin-engined designs took over their routes. As of this writing the
only trijets left in service are cargo conversions of the DC-10 and a few
small business jets.
The DC-10 was controversial. Of the two major widebody trijets the general
consensus nowadays is that the Lockheed Tristar was the better aircraft,
with a more elegant engine layout and superior avionics. Unfortunately
Lockheed had designed their airliner around a new Rolls-Royce engine that
took longer to develop than planned, so it entered service a year after the DC-10, in 1972. With its head start the DC-10 went on to outsell the Tristar more than two-to-one, but it had problems.
A poor cargo door design crippled one aircraft in
1972 and led to the total loss of another in 1974 with the deaths of all on board. The door was engineered
in such a way that it could be closed without locking solidly shut, after which cabin air pressure would eventually burst the door open. Another fatal accident in early 1979 resulted in the DC-10 being temporarily grounded, and a few months later a DC-10 involved in a sightseeing tour of Antartica crashed, again with the loss of all aboard. The two disasters of 1979 were technically not the fault of
the aircraft - one was caused by poor engine maintenance, the other
by incorrect navigation data - but the gruesome details of the crashes shook public confidence in the DC-10.
A further accident in 1989 highlighted a lack of redundancy in the
aircraft's flight controls; although the aircraft had three hydraulic
systems, the pipes were bunched together underneath the tail-mounted
engine, with the result that an uncontained explosion of the engine's fan
disk cut all three lines. In that case the pilots managed to avert
total disaster by using differential engine thrust to steer left and right, but nowadays the DC-10 does not
have a particularly positive reputation.
Unusually for Douglas there were only three major models of
the DC-10, none of which were stretched. Douglas had plans for more, but competition from the Tristar
and latterly the Airbus A300 ate into the company's market share, and by
the end of production in 2000 the three-engined configuration was out of date.
The DC-10-10, 10-30, and 10-40 were all the same size and had the same
payload, but were differentiated by engines and fuel capacity, with the base model
having a range of around 3,500 miles versus 5,000 for the 10-30 and 10-40. The 10-10 was capable
of transatlantic flight, but was mostly used on domestic routes in the
United States, whereas the -30 and -40 were comfortably able to cross the
Atlantic from anywhere in the United States to anywhere in Europe, or from
Europe to the Far East.
There was also a military variant, an the KC-10 Extender, a multi-purpose cargo aircraft stroke aerial refuelling tanker. It was introduced in 1977 as a larger analogue of the Boeing 707-derived KC-135. Unlike the civilian DC-10 the KC-10 had a fantastic safety record. Of the sixty purchased by the USAF only one was lost, and that was the result of a ground fire. It was withdrawn from service in the 2020s in favour of a replacement based on the Boeing 767.
An MD-11
McDonnell-Douglas introduced a second-generation DC-10 in the 1980s. At the time the company found itself in a bind. The DC-8 was leaving service; the DC-9 was still
popular, but growing old; the DC-10 was being pushed aside by competition
from Airbus. Lacking the resources to develop a ground-up successor the
company decided to stretch the DC-10 and give it more efficient wings. The
resulting MD-11 entered service in 1990.
Lockheed had discontinued the Tristar in 1984, leaving the long-range trijet market entirely to Douglas. But it was a market without a future, and the MD-11 only sold 200 units. With a range of around 6,000 miles and a capacity of 300-400
passengers the MD-11 competed directly with the Airbus A330, A340, and Boeing
777, selling fewer units than any of them, far fewer in the case of the A330
and 777. After the merger with Boeing in 1997 the MD-11 remained on
the market, with the last model - a freighter - rolling off the
production line in 2000. That was the end of the McDonnell-Douglas name,
although as mentioned earlier the Boeing 717 remained in production until
2006.
There were proposals for one more aircraft, the MD-12, a
four-engined, twin-deck super-jumbo that resembled the Airbus A380. Given
the problems that affect the A380 the general consensus is that it would
have been a disaster, and in the end nothing came of it.
And that was Douglas, a company fascinating both for its aircraft and also as a business case. In fact Jonathan Leonard and Adam Pilarski's Overwhelmed by Success: What Killed Douglas Aircraft (PDF) is an interesting read even if you don't care about the aviation industry. I'm not an expert, but among the reasons mentioned above it strikes me that Douglas' airliners all shared one common problem, which is that their general configurations had a limited shelf-life.
- The DC-8, for example, had been designed at a time when a mid-to-large-sized jetliner needed four engines. But in the 1970s a new generation of high-power turbofans meant that two engines could do the work of four, at less cost and with less complexity, so quad-jets such as the DC-8 gradually died off. Boeing kept itself relevant with the twin-engined 757 of 1981, but Douglas gave up on the mid-sized market in the early 1970s and never developed a 757 competitor.
- The DC-9 was designed with rear-mounted engines, but this configuration was hard to service and hard to load, because rear-engined aircraft have a habit of tipping over backwards. It also meant that the wings needed to be extra-strong and therefore extra-heavy, as there was nothing to counteract their tendency to bend upwards in flight. The DC-9's basic design therefore ended up as a dead end, and nowadays only business jets and small regional jets have rear-mounted engines. The conventionally-engined Boeing 737 and Airbus A320, in contrast, are two of the best-selling airliners of all time, and are still in production.
- The DC-10's trijet configuration only made sense in a certain time period, after which trijets were replaced with a new generation of high-powered, high-capacity twinjets. Douglas actually proposed a twin-engined DC-10, but this was in the early 1970s, at a time when manufacturers were sceptical of high-capacity twinjs. By the time a twin-engined widebody airliner might have won orders, Boeing had the 767 and Airbus had the A300, which were both much newer than the DC-10, and a few years later the two companies had the 777 and A330 twinjets, which were even larger.
Ultimately Douglas designed three popular airliners, but instead of replacing them when necessary it found itself compelled to upgrade them, until it was too late. Of
the company's jet-powered products only the DC-9 remains in passenger service in
2025, albeit as the Boeing 717, although several DC-10 derivatives are
still flying as cargo aircraft.
Next, Embraer.
